The 4.1 rivers, that is, the Yanhe River, the Huaihe River, the Yanshui River, and the Yanhe River, are of paramount importance in their functions, and each has its own unique characteristics, which are described below.
The Yanjiang River is also the largest river in China. Its upper valleys and abundant water resources can be repaired with many water conservancy projects, so that it can be repaired. Such as the three large rivers, the power is all over the place, benefiting people's livelihood. And its important water channels, the river is deep, and the boats are never far away. The cities along the river are conveniently transported, and the water is easy to flourish. In the middle and lower reaches, the land is fertile, the water is abundant, and the irrigation of the fields is convenient. It is important to nurture many cities and culture.
The Yanhe River is the best of the summer civilization. The land in the basin is flat, and the water is diverted from the river for irrigation, which is prosperous. The river is also often flooded into a river. In ancient times, the ancestors controlled river diseases, and the embankment repaired canals. In the process of governing the river, it was exhausting to manage water and promote the development of water conservancy technology. And the river is rich in the source of water, and the construction of the supply of materials and infrastructure.
The Huai River, which connects the north and south river systems of China and China, has an extraordinary distribution of water sources. The surrounding rivers are well-irrigated, which is conducive to the production of water. And the water is the main road, promoting the communication between the river basin and various places. However, the Huai River also often encounters floods. The ancients repaired ponds, dikes and other water conservancy projects to prevent floods, and also benefited irrigation and navigation.
Water, the ancient status was respected. Its flow rate is not as good as that of rivers and rivers, but it flows into the sea, which has a special geographical significance. The land in the basin is plump, irrigation is convenient, and the people on the banks are nourished. The waterway is also a traffic channel, promoting cultural exchanges between the regions.
The waterway, southwest of China and the United States. It is an important role in promoting cooperation and cultural exchanges between the two regions. The beautiful light along the river is also conducive to the development of tourism, and the local area.
In this regard, the 4.1 River, or the source of irrigation, or the source of transportation, or the source of wealth, has immeasurable benefits in many aspects such as cooperation, engineering, transportation, culture, etc. It is the key to heaven and earth, and the importance of the family.

Water, also known as mercury, is one of the elements of gold, and has the same physical properties.
It is often liquid, and under normal conditions, it is a white and bright liquid. This is its most striking characteristic. This liquid property allows water to flow freely in the container, with a smooth surface and high reflectivity.
The density of water is high, at 13.59 grams/cubic centimeter, and it is heavy for many ordinary substances. Due to its high density, it forms small droplets if poured on a flat surface, and is not easy to disperse.
Furthermore, the melting temperature of water is very low, at -38.87 ° C, and the boiling temperature is 356.6 ° C. This special melting temperature makes it difficult to hold liquid in the phase. Even in cold environments, it solidifies by solidification and needs to be reduced to a low temperature to begin solidification; and to make it boil and vaporize, it needs to be added to a high temperature.
Water has excellent performance. In terms of energy, it can be quickly reduced, and it can be used for some high-efficiency combination or placement; in terms of energy, it can be used for good flow, in specific sub-components or routes, or in action.
In addition, the surface force of water is large, causing its droplets to be nearly spherical, because it minimizes the surface to reduce the surface energy. This property makes it difficult to reduce the surface of the solid surface, and maintains the droplet shape.

The water of the Yellow River has a long history, and its chemical properties are worth exploring.
The water of the Yellow River is a complex mixed system. Among them, water is the main body, its nature is peaceful, colorless and odorless, and it is the source of life for all things. However, the water of the Yellow River is not pure water, and contains many solutes.
The first mineral, its water is rich in cations such as calcium, magnesium, potassium, sodium, and anions such as carbonate, sulfate, and chloride ions. This mineral composition makes the water of the Yellow River have a certain hardness. Cover calcium ions and magnesium ions, which can precipitate in case of soap, which affects the washing effect. However, an appropriate amount of minerals is also beneficial for biological growth and can provide necessary nutrients for aquatic organisms.
Furthermore, the Yellow River water contains trace amounts of iron, manganese, zinc and other heavy metal ions. Although its content is usually not high, it also has potential effects on the ecological environment and human health. If the environment changes, the concentration of heavy metal ions will increase, which may endanger the health of aquatic organisms and surrounding residents.
Looking at its pH, the Yellow River water is roughly weakly alkaline, with a pH value between 7.5 and 8.5. This weakly alkaline environment is suitable for the survival and reproduction of many aquatic organisms. Alkalinity helps to neutralize acidic substances and maintain the ecological balance of the water body.
In addition, the Yellow River water contains a large amount of suspended solids such as sediment due to its wide flow through the region. Although sediment is not a chemical substance in the strict sense, it has a significant impact on the chemical properties of water. Sediment can absorb part of the solute in water, changing its distribution and migration; and sediment participates in many chemical reactions, which affect the redox environment of the water body.
The chemical properties of the Yellow River water are complex and are affected by many factors such as geology, climate, and human activities that flow through the region. It contains nutrients needed for life, but also potential environmental risks. It should be treated with caution and properly protected and utilized.

If you want to make the tools of the river, there is a way to study them. The good workmanship of the ancient times, the quality of the tools, the first material to be obtained. If you want to get the best quality, you will often find the famous mountains and mountains. Observe the color of the stone and the ground, and then you will find it. If you get the stone, you will first break the small stone, and this will be broken. If you break it, you will be smelted into the mould. Those who make it, with a solid and refractory material, can hold high and not stale. In the mould, you must control the heat. At the beginning of the fire, make the stone stale, and the fire is strong, so that it melts into a liquid. In other cases, it is necessary not to mix it, so that the liquid is uniform, and it is easy to float on the surface, so that it can be skimmed off.
After leaving, take the raw liquid and put it into the mold. The mold is made of clay or wood, and it is carefully carved according to the shape of the tool. The liquid is put into the mold, and it is cold. The speed of cooling is also the speed of the tool. The speed of cooling, the tool is easy to crack; cold, and the hardness of it is afraid to be affected. When the liquid is completely solidified, the mold comes out, and the rough embryo is formed.
However, the rough embryo still needs to be polished. First, use a rough stone to grind the rough surface of the device to make the body flat. Rub it with sand, so that it is bright. Polished, the craftsman must pay attention to it, and strive for every piece to be smooth and flawed. If there is a treasure, it can be engraved to make the object beautiful. Or engraved with auspicious and rui, or engraved with flowers, they are all lifelike, and the artifacts add a lot of color.
The artifact of making rivers, from the source to the finished artifact, needs to be carefully done step by step, and the wisdom and skills of the craftsman can be integrated into it to obtain exquisite and durable products.

The water is filled with sand, and there are many things that need to be paid attention to.
The first thing to do is to clearly observe the place where it is hidden. Take the land, and seek to be flat and dry, so as to avoid the trouble of water immersion. If the land is low, the water is easy to gather, and the amount of sand may be affected by it, or the mud will be damaged, and it will not be used. And the hiding place is convenient and good, so that the moisture in the sand is easy to dissipate, so as not to condense the tide.

It is necessary to fix the equipment to prevent the leakage of sand on the way. The, so that the level, if the pile is uneven, the line is easy to produce oblique bumpy, not easy to scatter sand, also endanger the safety of.
Furthermore, the sky cannot be ignored. On rainy days, the road is slippery and slippery, and the sand increases its weight in contact with water, and it is easy to stick. Therefore, it is advisable to reduce the speed on a sunny day to ensure profit.
The speed of the speed also requires a degree of speed. The speed is easy to cause the earthquake of the sand to be scattered, and it is necessary to control it when it encounters a problem. It consumes a lot of force, only increasing the cost. If the speed is high, the speed is controlled to be safe.
The handover is high, and the core quantity is high. If the quantity does not match, it will involve a profit; if the quantity is poor, it will affect the project. It must be high, and it can be handed over only when it is safe.
All these things must be done with care in the water and sand.